Casters, in their basic form, are generally understood in the art to include one or more wheels swivelably or pivotably mounted to an object so that the object can move across a surface in any direction. Often, casters are capable of being locked in one or more orientations so that the movement of the wheels, and thus the object coupled thereto, is generally limited to a direction corresponding to that orientation.
Various available locking swivelable casters employ a locking mechanism that requires the caster to be set in the orientation in which it is to be locked prior to or at the time of locking. For example, certain casters will not allow a locking mechanism to be activated unless the caster is in the orientation in which it will be locked. It can be time consuming and frustrating for a user to properly orient the caster prior to engaging the locking mechanism.
Additionally, hospital beds including stretchers (or other hospital equipment) often utilize swivel casters to accommodate movement of the hospital bed in multiple directions. However, when such a hospital bed is being moved in a straight line, such as down a straight hall, pivotable casters can often cause the bed to drift or move in directions other than the intended direction, making straight line movement difficult to control or achieve. As the hospital bed is pushed faster (as may occur in emergency situations), the difficulties in maintaining a straight line may become more apparent. Further, turning corners can be difficult as the casters do not provide a lateral force to the direction of travel which can be used to convert momentum in one direction to momentum in another direction. In essence, the individual or individuals pushing and/or pulling the hospital bed must often bring the bed to at least a near stop, reorient the bed in the proper direction, and then resume movement.
Current solutions exist to aid in straight-line travel such as placing one or more non-swivelable or non-pivotable wheels at or near the center of the hospital bed that selectively engage and disengage the surface of the floor. When engaging the floor, these non-swivelable wheels act as a keel of sorts to provide lateral resistance during movement of the hospital bed to aid in straight-line movement and while turning corners. These current solutions, however, require mechanisms to move the wheel to selectively engage and disengage the surface. Additionally, at the moment the wheel is activated to engage the surface, the movement of the hospital bed is immediately limited as described above. Thus, engagement must occur exactly when restricted movement is desired. Though suitable for at least some purposes, such an approach does not necessarily meet all needs of all application settings and/or all users.
Elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions and/or relative positioning of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present teachings. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments of the present teachings. Certain actions and/or steps may be described or depicted in a particular order of occurrence while those skilled in the art will understand that such specificity with respect to sequence is not actually required. The terms and expressions used herein have the ordinary technical meaning as is accorded to such terms and expressions by persons skilled in the technical field as set forth above except where different specific meanings have otherwise been set forth herein.